DESCRIPTION: (Adapted from applicant's description) The long term goals of this application are to elucidate the molecular mechanisms underlying neuronal specification. Toward these goals, the investigator plans to perform a mini-screen to determine whether novel and known targets of the Drosophila vnd NK-2 gene can be identified using yeast genetics to functionally screen for sequences that mediate transcriptional activation in a factor-dependent manner. If the sequences are novel, large genomic clones corresponding to vnd/NK-2 binding sites will be identified and the map position determined on polytene chromosomes. The expression pattern of both known and novel genes associated with putative vnd/NK-2 binding sites will be determined by in situ hybridization relative to vnd/NK-2 expression patterns.